The present invention relates to improvements to a fireplace construction such as the type that is often installed in a masonry or zero clearance fireplace opening. The invention modifies the existing firebox construction by providing an intermediate wall which is spaced forward of the rear wall of the firebox and extends between and, in some embodiments, completely closes a space between the side walls, the top wall and bottom wall or floor of the firebox. The fireplace unit itself, sometimes referred to as a firebox insert, has an opening on one side formed by spaced side walls, a rear wall, and top and bottom walls with connection means in the top wall for communicating the firebox with a chimney or other exhaust outlet. The present invention resides in the construction and installation of the intermediate wall member.
The intermediate wall member is preferably of a curved or arcuate shape or a wall formed of angularly related segments. In some embodiments, the bottom edge of the intermediate wall member extends closer to the rear wall of the firebox opening at or near the bottom or floor thereof as compared to the top edge which extends closer to the front portion of the firebox near the top thereof. This means that, in this particular arrangement, the upper portion of the intermediate wall member overhangs the area in the firebox where the fire takes place. In other embodiments of the present invention, this is not necessarily true as will be hereinafter further explained.
Of great importance to the present invention is the fact that the overall size and shape of the fireplace insert need not generally be changed from a conventional construction to accomodate the present intermediate wall member. This means that the fireplace can be made to fit a conventional masonary or other wall opening. The intermediate wall member preferably should fit snuggly into the firebox opening and may be attached to the other walls and deck of the firebox by fasteners, by welding, or by other suitable means. Installation can be made to existing fireplaces or the intermediate wall member can be installed or otherwise fabricated in the fireplace by the manufacturer. Use of the intermediate wall member increases the reflective and radiant characteristics of the interior of the firebox and it prevents flames and embers from entering the space behind the intermediate wall member.
The present intermediate wall member preferably extends to the bottom wall or floor of the firebox to maximize the size of its reflective or radiant surface, and, in most cases, it will also reduce the overall size of the floor of the fireplace thereby making the fireplace somewhat easier to clean. In the embodiments of the present invention where the intermediate wall member actually abuts the top wall of the firebox, it is preferred that such intermediate wall abut the top portion of the firebox along as much of its length as possible to both provide additional stability and rigidity to the intermediate wall and to again maximize its effectiveness over the area where combustion takes place thereby also increasing the efficiency of the fireplace. The construction and positioning of the intermediate wall will also help prevent downdrafts from reaching the firebox where they can blow out a pilot light or cause other problems such as blowing fire and ashes into the room. This can be a problem especially when a gas source is used as when the fireplace is used with a gas or artificial fire. Similarly, in those embodiments of the present invention where the intermediate wall member abuts or at least extends forward of the exhaust flue or chimney opening in the firebox, the top edge portion of the intermediate wall member should have at least a portion thereof which is not attached to the top wall of the firebox or does not block or otherwise interfere with the flue or chimney opening so as to provide communication between the firebox and the exhaust flue so that the products of combustion can escape.
The intermediate wall member may be made from a single thickness sheet metal member or it may be constructed of spaced connected wall panels with a space formed therebetween, which space may be left empty for air to circulate therethrough, or it may be filled with an insulating material. If an airspace is provided in the present wall member, then suitable holes or passageways should be provided to permit the air to circulate therebetween. The important thing is that the intermediate wall member extend between the side walls and, in some embodiments, between the floor and the top wall of the firebox as well, and that it be spaced forward of the rear wall so as to form an airspace therebetween.
In some embodiments of the present invention the upper overhanging portion of the intermediate wall member can be constructed to have an irregular, contoured shape such as an egg-carton like shape or other grid type construction so as to form overhead air pockets or air traps for the air that has been heated. This is done to increase the surface area for heat transfer and to retard the movement of hot gases as they move upwardly in the firebox before they enter the exhaust flue or chimney. Retarding or slowing the movement of these hot gases keeps such gases in contact with the intermediate wall over a relatively large surface area thereby increasing the heat transferred to the wall and further increasing the efficiency of the firebox. Such an irregular or pocketed shape for the upper portion of the intermediate wall member also operates to further oxidize the escaping gases. It is not generally desired, however, to extend the irregularly shaped portion of the intermediate wall downwardly too far into the firebox because to do so will only provide more places for the ashes and other products of combustion to be trapped making the firebox harder to clean and maintain.
The present intermediate wall means also has application to other devices such as to top-feed wood pellet stoves and other devices where fires are burned in open sided fireboxes.
It is therefore a principal object of the present invention to provide wall means for installing in fireplaces and in certain stoves and in other heating devices to increase their operating efficiency.
Another object is to provide means for modifying an existing fireplace construction such as a conventional fireplace construction of the type installed in masonary openings and the like, to improve its operating characteristics and efficiency.
Another object is to make it relatively easy to clean the combustion chamber of a fireplace or like device.
Another object is to improve the heat reflecting and insulating characteristics of fireplaces.
Another object is to provide a wall structure for installing in fireplace openings and the like which can be made adjustable to fit different size and width firebox openings, which wall structure substantially isolates the spaces on opposite sides thereof.
Another object is to teach the construction and installation of a relatively simple and inexpensive wall for installing in the firebox portion of a fireplace assembly.
Another object is to provide a wall structure for installing in fireboxes and the like which has good insulating characteristics.
These and other objects and advantages of the present invention will become apparent after considering the following detailed specification which discloses several different embodiments of the present invention in conjunction with the accompanying drawings.